DE102004058864B4 - Method and device for fuel consumption-oriented cooling of internal combustion engines by means of a switchable additional valve - Google Patents

Abstract

Method for operating a cooling and heating circuit for motor vehicles with an internal combustion engine (1), which is cooled by means of a coolant circulated by an engine coolant pump (7), with a self-sufficient thermostatic valve (6), which controls a coolant temperature and a coolant throughput through the internal combustion engine (1) and regulates a vehicle radiator (8) and a bypass branch (6b) with an additional valve (6bv) which can be influenced by an electronic engine control (20) and which additionally varies the coolant throughput through the internal combustion engine (1) depending on its cooling requirement, characterized in that a heating heat exchanger circuit and other coolant branches through which flow can flow when the autarkic thermostat valve (6) is closed are arranged parallel to one or more pressure sinks in a flow branch that can be influenced by the additional valve (6bv) and that the heating heat exchanger circuit and this other when the autarkic thermostatv Entil (6) through which coolant branches can flow when there is a reduced cooling or heating requirement, despite the rotating engine coolant pump (7), a reduced pressure difference up to a pressure difference of zero is imposed so that the additional valve (6bv) partially or completely closes.

Description

The invention relates to a method and a device for operating a cooling and heating circuit for motor vehicles with an internal combustion engine which is operated by means of an engine coolant pump 7th circulated coolant is cooled with a self-sufficient thermostatic valve 6th , which controls the coolant temperature to control the coolant throughput through the internal combustion engine 1 and the vehicle radiator 8th controls and one from the electronic engine control 20th influenceable bypass branch 6b with additional valve 6bv, which additionally varies the coolant throughput through the internal combustion engine depending on its cooling requirements. It is preferably used in internal combustion engines with a conventional expansion material thermostat.

It is known to use thermal management measures to reduce fuel consumption in modern cars. Rapid heating of the coolant and engine oil, and thus also of the engine components, as well as raising the thermostat opening temperature under partial load are tried and tested means of improving fuel consumption.
Future strategies for achieving the full fuel-saving potential by means of such measures include in particular the possibility of freely selecting the opening time of the thermostat by means of the engine control and of varying the coolant throughput through the engine over a wide range during warm-up. Various solutions are available for this, from the magnetic clutch to switch off the coolant pump of the engine to the pump-internal short-circuit valves to the fully variable electronic water pump as a replacement for the belt-driven cooling water pump.
All known solutions for regulating the coolant throughput through the engine have in common that considerable costs are incurred for the necessary additional components. In addition to the measures for regulating the flow through the engine, most of the known optimization strategies provide in particular for the replacement of the thermostat commonly used today with regulation of the cooler flow by means of an expansion element through a valve that can be freely controlled by the engine control. In order to fully exploit the potential, relatively complex valves in particular are provided in this context, in which the flow through the cooler is specified by the motor control and is sensitively adjusted via a stepper motor. Different rotary positions of the multi-way valve then set, for example, preferred positions for optimal hot cooling, maximum cooling effect or maximum cabin heating output. The costs for such a valve to switch multiple inflows and outflows for the cooler, bypass and heating circuits, or to vary them continuously, are not insignificant. In addition, there is a further additional effort if sufficient fail-safe behavior is to be implemented for all possible summer and winter operating conditions.
The costs are therefore already considerable, even if the full fuel-saving potential is foregone, and an additional measure for varying the coolant pump speed or the coolant pump delivery rate is also provided at the same time as the introduction of the valve.

Not least against the background of costs and operational safety, a much simpler system for hot cooling has prevailed on the market, in which an expansion thermostat with an electrically heated expansion element enables the optional operation at two different coolant temperatures. A thermostat with an expansion element is used, which inevitably begins to open from 100 ° C, for example. The fuel consumption advantages are not fully exploited here, partly because the effectiveness of the system is limited to driving situations with coolant temperatures above approx. 80 ° C, but the additional costs are also significantly lower. In addition, any discussion regarding the robustness of the system and its fail-safe characteristics as well as the question of the availability of components ready for series production are largely irrelevant in view of the already existing series experience with this type of electrically heated thermostats.
Nevertheless, the system suppliers for vehicle cooling systems are working on the variants described above to fully exploit the fuel-saving potential of thermal management measures. However, the success of these new approaches is, on the one hand, largely linked to the development of emission regulations and fuel prices, and on the other hand, is also very much linked to the provision of hardware that is much cheaper than previously available. Conversely, the failure to start large-scale production makes falling hardware prices for the electronic multi-way valve as a thermostat replacement and possibly the switchable or controllable cooling water pump more difficult.
Even if a well-known motor vehicle manufacturer is now investing a great deal of effort into a cooling system with an electrically driven engine cooling water pump for an entire engine family in order to save as much fuel as possible, the high costs in many places prevent the introduction of such a system.
Not least because of this, more economical systems, such as the electronic thermostat in a three-plate design, have recently come into series use. In such systems, one of the three plates - the so-called closing plate - closes and opens the small coolant circuit in the early warm-up phase with increasing motor heating. By means of electrical current supply to the expansion element when there is a high thermal load on the engine, the bypass branch is opened further if necessary or closed again when there is a very high cooling requirement and the cooler circuit is wide open. The electrical current supply helps in particular to counter previous problems with the three-plate thermostat when quickly switching from partial load to full load, especially when the engine is cold. The limited response speed with cold cooling water, however, still does not allow the use of the three-disk thermostat with every engine without additional design measures.
Systems with a freely controllable bypass valve, for example as a steplessly controlled rotary slide valve, are also known which do not have this problem, but are again less favorable in terms of costs.

All known systems, including the three-plate thermostat, have in common that special interventions in the heating circuit are necessary in order to prevent the amount of coolant circulated in the heating circuit from having a negative effect on fuel consumption. In order to achieve the smallest possible water-side heat transfer coefficients within the engine during warm-up, and to minimize the heat-active masses and heat losses of the heating circuit, separate devices are provided in the previously known thermal management systems that allow the coolant throughput through the heating branch to be prevented or during warm-up at least to throttle strongly. Especially with air-side control of the cabin heating, this generally means that additional costs for coolant valves or other components to prevent / throttle the heating volume flow.

In this environment, the U.S. 4,726,324 A a particularly complex cooling and heating system, each with a separate cooling circuit for the cylinder block and the cylinder head, with each cooling circuit being assigned its own coolant pump, its own vehicle radiator and its own thermostatic valve. The two thermostatic valves are each designed as a mixing valve which regulates a coolant flow in a bypass and a cooler circuit. Only a heating system heat exchanger is used. The heating heat exchanger is assigned two coupled switchover valves which, depending on the operating situation, can connect the heating heat exchanger to the cooling circuit for the cylinder head or the cooling circuit for the cylinder block.

the DE 10 2004 030 153 A1 shows a cooling system in which the flow through a transmission oil cooler, which is integrated with a vehicle cooler, can be activated with an additional valve, while a thermostatic valve for the cooler circuit is closed. This additional valve is opened depending on the coolant or oil temperature either mechanically (e.g. via a wax cartridge) or electrically (via an engine control) and leads to a flow through the vehicle radiator and the transmission oil cooler under the pressure of the engine coolant pump, with the thermostatic valve still closed . When the additional valve is opened, the flow through a ventilation circuit connected to the vehicle radiator and leading via an expansion tank is initiated. Conversely, when the additional valve closes during warm-up (and thus when the thermostat valve is closed), this venting circuit leading via the vehicle radiator and an expansion tank is simultaneously prevented.

the DE 103 11 188 A1 shows a cooling and heating circuit of an internal combustion engine with a cooler circuit with a vehicle radiator and a thermostatic valve and a bypass circuit leading through the internal combustion engine and a bypass branch with an engine oil cooler, which bypasses the vehicle radiator. With the closing of the additional valve during warm-up (and thus closed thermostatic valve), among other things, the coolant throughput in the internal combustion engine and in the engine oil cooler can be controlled, combined with controllability of the heat transfer in the engine oil cooler and inside the engine. The engine control intervenes with separate actuators and / or special measures such as heating heat exchangers with increased pressure losses in the coolant throughput of the engine (of the bypass circuit, the heating circuit and, if necessary, the cooler circuit).

In contrast, the object of the present invention is to create a particularly cost-effective and yet operationally reliable cooling and heating system in which as much of the fuel-saving potential as possible can be used by thermal management measures at coolant temperatures below the thermostat opening temperature common today in cooling systems without electronic thermostats.

This object is achieved with the methods and devices according to the independent claims.

The other requirements also offer further advantages depending on the design variant.

In some of the exemplary embodiments, the method according to the invention can in particular also be used to realize part of the fuel-saving potential for which a coolant temperature is above that of today's cooling systems Without el. thermostats usual thermostat opening temperature is required.

The values of the electrically heated thermostats as they can be found on the market today, i.e. in particular setting the coolant temperature to values between 80-85 ° C by means of the engine control, are currently to be regarded as key points for temperatures and costs that are particularly to be strived for or to be surpassed at high load and 100-115 ° C in partial load.
In particular, the performance features in terms of fuel savings and quick switchover from partial load to full load as well as the overall system costs of the three-plate thermostat, which was used in large-scale production for the first time this year, can be exceeded.

In addition, the requirements with regard to the cabin heating effect are fully met. Some of the application examples also make it possible to improve the heating effect or to switch between a first operating mode with significantly improved fuel consumption and a second operating mode with improved heating power and slightly less improved fuel consumption in the partial load.

In connection with a part of the associated claims, it is even possible to switch between a first operating mode with significantly improved fuel consumption and a second operating mode with improved heating power and somewhat less improved fuel consumption.

In a method according to the invention, the option of temporarily setting the coolant flow through the bypass branch of the engine cooling and through the heater to zero with a simple on / off two-way valve without further actively controlled additional components is particularly attractive.
In extreme cases, starting with today's series cooling systems, it is sufficient to insert the additional valve 6bv and relocate the heating heat exchanger connection to the unusual position downstream of the additional valve 6bv.
In the simplest variant without an electric heating pump, it is important that it is behind the additional valve 6bv and the inside of the thermostat 6th there is a sufficient pressure drop so that there is a sufficient pressure difference for the heating system heat exchanger when it flows through the bypass branch. The pressure drop on the relatively generously dimensioned bypass branch, ie for large coolant throughputs even when the radiator is closed, is known to determine the position in the pump map of the engine coolant pump and less the relatively small flow in the heating branch.

Since the pressure available for the heating circuit is hardly sufficient in today's series applications anyway, it does not seem expedient at first glance to insert an additional valve - associated with corresponding pressure losses - and then connect the heating only after this valve. At first glance, one is more inclined to increase the available pressure difference for the heating by closing the additional valve in order to increase the heating heat exchanger performance.

The embodiment according to the invention still goes this way, since it opens up a way to save fuel which is extremely favorable in terms of its cost / benefit balance.
An operating mode without any engine flow through with coolant can thus be set by closing just a single additional open / close valve in the warm-up phase. The associated fuel savings are well known. Natural coolant convection and the thermal inertia of the engine components including the engine's internal coolant and engine oil ensure that the engine does not overheat with moderate engine load, e.g. in the first ECE cycles of the statutory emissions test. In phases when there is an increased need for cooling, the additional valve is then opened suddenly or cyclically, for example by the engine control. When fully opened, the system behaves like a completely conventional cooling system.
If the pressure loss at the additional valve is correspondingly small, an existing series thermostat with a conventional additional valve can be used without any changes. In the case of standard thermostats without a bypass, it may be necessary to ensure that a sufficiently large pressure drop behind the additional valve ensures that there is a sufficient pressure drop to ensure that there is flow through the heating system heat exchanger when the additional valve is open.

As tests on series vehicles show, this configuration of the cooling and heating circuit is possible with a corresponding selection of the additional valve, in particular when configured as a rotary slide valve or ball valve, without any loss of heating comfort. If the control of the additional valve is carefully adapted by means of the engine control, in a first operating mode with the additional valve open, this leads to good or adequate cabin heating with full cooling functionality. When the valve is closed, the heating is deactivated and fuel consumption is reduced at the same time.
The activation of the additional valve by means of the engine control offers the particular advantage that the engine can switch to full coolant throughput at any time, regardless of the coolant temperature. In particular, motors with a very high specific power can be protected very well in the event of a sudden load change. Those of el. Thermostats There are no known dead times when opening and closing, so that, for example, it is possible to drive longer with standing water. If necessary, an open / close control of the additional valve can also take place.
As a further advantage, the risk of cavitation on the engine cooling water pump at high engine speeds can also be controlled more reliably with this configuration than with the three-plate thermostat, for example.

Even if the simplest variant of the cooling and heating circuit according to the invention described so far does not open up the full fuel-saving potential and compared to earlier patent applications with a switchable additional valve and adjustment of the coolant flow rate in the heating system heat exchanger, in addition to lower fuel savings, in general. also does not give a better cabin heating effect, so the simplicity and the cost aspect make this embodiment particularly attractive. The costs for an on / off valve are so low, in particular, because such valves are already being used in series production and investments in development and production can therefore be kept very low. The risk of failure is also very small. This can be further reduced by using valve types that are open when de-energized. This applies in particular to solenoid valves or valves with vacuum actuators.

The previous versions focused on placing the heating heat exchanger feed line at a point downstream of the additional valve while at the same time placing the heating heat exchanger return line on the suction side, the engine cooling water pump, either directly at the pump inlet or at the inlet to the thermostat upstream of the pump 6th .

In an analogous way, the method according to the invention can also be used in variants but also vice versa, i.e. with the heating heat exchanger return line being placed at a point upstream of the additional valve with simultaneous positioning of the heating heat exchanger supply line on the pressure side of the engine cooling water pump, optionally directly at the pump outlet or on the water jacket of the cylinder liner. With the additional valve 6bv closed and the cooler circuit closed 6a This results in a pressure difference of zero at the heating system heat exchanger 4th one, as well as inside the engine 1 . In other words, by opening and closing a single on / off auxiliary valve, you can switch between a fuel consumption-oriented setting without heating and a setting with normal cooling and heating operation.

To further deepen the ideas according to the invention, some particularly advantageous configurations are described below with the aid of exemplary cooling and heating circuits.

This shows 1 a possible cooling circuit according to the invention with a focus on improving fuel consumption with the option of switching to normal operation, ie to full functionality of the cabin heating and cooling.

When the additional valve 6bv is open, the coolant is in accordance with 1 from the engine coolant pump 7th by the internal combustion engine 1 promoted and flows through the additional valve 6bv in the bypass branch 6b to conventional expansion thermostats 6th . During the warm-up, the plate on the cooler side of the expansion thermostat closes the cooler circuit while the plate on the bypass side is open. The vent line 9a of the expansion tank 9 is connected downstream of the additional valve 6bv. The coolant flows from the expansion tank together with the water from the heating return into the thermostat. This line is usually when the thermostat is open as well as when it is closed 6th to the engine coolant pump 7th open. The cooling water for the heating circuit is also downstream of the additional valve 6bv 4a taken. The heating heat exchanger 4th is flowed through in a conventional manner with this setting. As long as the additional valve 6bv generates only a relatively small pressure loss in the open state, no further redesign of the components has to be undertaken in order to achieve the full heating output. A rotary slide valve is therefore preferably used as an additional valve which, when open, releases the full channel cross-section of the bypass line. Since the rotary slide valve is only operated open / closed, it can be manufactured very easily and inexpensively, the easiest way being with a vacuum actuator that is controlled by the engine control 20th controlled solenoid valve is supplied with negative pressure. When warming up without the need for cabin heating, the additional valve 6bv is activated by the engine control at low to medium engine load 20th closed. So that's not just the bypass circuit 6b interrupted but also the heating circuit 4a , the ventilation circuit 9a , the cooler circuit 6a and the flow through the oil cooler 40 . With the exception of a local flow in the vicinity of the pump impeller and natural convection, there is stagnant water in the cooling circuit. This reduces the water-side heat transfer coefficient in the engine in a known manner and the engine-internal coolant and component temperature increases. The reduction in friction through a warmer cylinder liner, slightly lower drive power of the engine coolant pump, warmer oil and, in gasoline engines, the thermal dethrottling of the intake air then ultimately lead to the characteristic fuel savings of this thermal management measure. As long as overheating of the motor is safely ruled out using suitable sensors or thermal models the additional valve can remain closed. If cavitation on the coolant pump is to be expected because the pump speed is too high, the engine control opens 20th the additional valve 6bv. The same applies if the thermal load is too high or if the engine is at full load. The high actuating speed of the additional valve 6bv compared to the potential alternative “El. Thermostat “extends the scope considerably until the thermostat is opened for the first time. Depending on the engine, different strategies are advantageous up to the first opening of the additional valve. The simplest strategy is to wait as long as possible until the additional valve opens and integrates the bypass branch along with the oil cooler, heating circuit and ventilation circuit and, if necessary, opens the cooler circuit a little. For better ventilation, it can be advantageous to work with the additional valve 6bv open for the first few seconds of warming up.

In particular, however, it can also be advantageous to initially keep the additional valve closed, then to open the additional valve when a first temperature below the thermostat opening temperature is reached, so that a first temperature equalization occurs in the bypass and heating branch and occurs on the oil cooler 40 ceases to transfer heat from the water to the oil. If necessary, the flow in the vent line must also be throttled here, or the return is - as in 7th shown - placed on the cold side of the radiator, which is the case with engine cooling water pumps that are insensitive to cavitation 7th may be permissible.

As long as there is no flow in the bypass branch and thus also in the heating branch, there is no risk of part of the heated cooling water escaping via a partial opening of the radiator thermostat. A sudden opening of the additional valve 6bv leads directly to an increase in the heat transfer coefficient in the water jacket of the engine and thus to a cooling effect. There is no risk of thermal shock because the thermostat 6th when the additional valve 6bv is open, it ensures successive admixing of cold cooling water from the radiator branch in a known manner.

If necessary, the additional valve is opened in a timed manner, so that the heating or cooler can also be switched on gradually. The procedure according to the invention does not claim to be the thermodynamically best way. Rather, the relationship between costs and benefits is always to be seen here. The procedure according to the invention is particularly advantageous when the focus is on fuel consumption without additional demands on the heating effect. If, at the same time, an improvement in the heating output were required, it would be based on 1 probably a process with connection of the heating system heat exchanger 4th upstream of the additional valve 6bv, closing of the additional valve 6bv to improve the heating performance, throttling of the coolant throughput through the engine and the heating heat exchanger and counterflow design of the heating heat exchanger 4th much more effective.

2 shows an analogous procedure to 1 with the difference that the internal combustion engine 1 even as a pressure sink to generate the pressure difference at the heating system heat exchanger 4th is used. The cooling water for the heating circuit 4a is here behind the engine cooling water pump 7th or taken from the water jacket of the engine block and, when the additional valve 6bv is open and the cooler circuit is closed, it again flows through the bypass-side plate of the thermostat 6th back to the coolant pump 7th . A partial flow goes through the ventilation circuit behind the additional valve 6bv 9a and another through the oil cooler 40 . These two partial flows flow into the always open branch of the thermostat, through which the heating return usually flows in conventional systems. Quite analogous to 1 is also sufficient for 2 simply closing the additional valve 6bv in order to ensure standing water in the entire system with the exception of the vicinity of the pump wheel. This results in quite analogous advantages for fuel consumption when the engine is warming up and, if necessary, in the warm partial load. Since there are usually relatively high coolant throughputs through the engine when the additional valve 6bv is open and only a relatively small amount of heat is supplied to the coolant under partial load, the alleged disadvantage that the cooling water for the heater is taken from the engine inlet hardly has any effect, since at the engine outlet and engine inlet are almost the same temperatures. On the other hand, it is also important here that the additional valve 6bv has only a slight pressure loss in the open state. If necessary, however, a heating system heat exchanger can also be used, which manages with a somewhat lower pressure loss.

Since an electric heating pump is often used anyway, especially in vehicles in the upper price range, in order to ensure that the cabin heating is maintained by circulating coolant when the internal combustion engine is not running, the pressure loss in the heating heat exchanger circuit often plays a somewhat subordinate role. 3 shows in this connection a particularly advantageous embodiment of the system according to the invention with the integration of the additional electronic pump 2 , which coolant is available at the same time as the closing of the additional valve 6bv by means of the control 20c is turned off. This embodiment of the system according to the invention offers the very special advantage that it not only makes it possible to work with standing cooling water, but also - in comparison to the open bypass branch - with small amounts of circulating water Cooling water. This is particularly advantageous for operating situations with heating, since advantages in terms of fuel consumption and heating effect can now be achieved. In particular, it is also possible to raise the coolant temperatures to a somewhat higher level by switching on the additional electrical pump during the warm-up process without the risk of local overheating. This applies to the integration according to 3 as well as for the arrangement according to 4th with reverse delivery direction of the electric pump 2 . In both cases, there is no risk of the cooler being opened unintentionally when there is flow through the heating system heat exchanger, because warm coolant is running along the thermostat 6th flows. In addition, the integration according to 3 the advantage that when the additional valve is closed, the motor flows from the head to the block. This brings fuel consumption advantages when switching on the initially cold heating circuit and especially when drawing off heat at the heating heat exchanger. These advantages are due, on the one hand, to the fact that, in view of the tribological requirements in the cylinder head, cold coolant is less harmful than in the area of the cylinder liner. Another advantage results from the fact that any sinking cold water does not remain at the bottom of the water jacket but is sucked off.

Conversely, especially with increased demands on the heating, the configuration is normally in accordance with 4th a little cheaper, as the cylinder block and the crankshaft / oil pan area are heated a little less. This is especially true when integrating the oil cooler 6th where that on the heating system heat exchanger 4th Cooled cooling water extracts additional heat from the oil. Especially with a relatively low flow through the heating heat exchanger, the amounts of heat transferred here in the direction of a better heating effect are quite significant. The integration downstream of the engine coolant pump 7th has the very special advantage that when the additional valve 6bv is closed, the flow through the engine can easily switch between the state according to FIG 5 and 6th can be switched, ie it can be switched very easily between a heating output-oriented and a more fuel-consumption-optimized operating mode. A simple polarity reversal of the additional electrical pump is sufficient for this 2 . For this purpose, it is particularly advantageous to use the additional pump 2 to be designed as a gear pump, G-rotor pump or axial impeller pump, since with these pumps a reversal of the conveying direction is very easy due to the principle involved. As long as the additional valve 6bv remains closed, the required pressure of the electrical additional pump is 2 approximately the same for both directions of flow through the heating system heat exchanger. It doesn't matter how fast the engine coolant pump is 7th turns. This particularly simplifies the implementation of flow control strategies through the engine or through the heating system heat exchanger, which is very helpful both for operation in the direction of better heating performance but also for operation in the direction of better fuel consumption.

• Bei einem Kaltstart bei -10°C Umgebungstemperatur und 50 km/h, d.h. rel. geringer Motorlast, wird in einem ersten Schritt das Zusatzventil 6bv geschlossen, die el.
• Zusatzpumpe fördert das Kühlmittel in der in 6 gezeigten Richtung. Damit wird ein sicheres Defrosten der Windschutzscheiben sichergestellt bzw. ein Beschlagen der Scheiben wird vermieden. Nach Erreichen einer Mindest-Kühlmitteltemperatur wird dann die Gebläseleistung allmählich hochgefahren, so dass der Luftmassenstrom in die Fahrerkabine hinein steigt, wobei gleichzeitig die Luftströmung nun nicht mehr primär durch die Defrosterdüsen geleitet wird, sondern auch in Richtung Fußraum und gegebenenfalls in Richtung Mannanströmer.
• Dabei ist es zur Maximierung der Kabinenheizwirkung vorteilhaft, wenn der Kühlmittelmassenstrom durch den Heizungswärmetauscher 4 so eingestellt wird, dass die Kühlmitteltemperatur an dessen Austritt spürbar unterhalb der Öltemperatur des durch den Ölkühler 40 strömenden Motoröls liegt. Je besser der Wärmenutzungsgrad des Heizungswärmetauschers bei relativ geringen Kühlmitteldurchflüssen ist, desto mehr Wärme lässt sich auf diesem Umweg über die Abkühlung des Motoröls für Heizzwecke gewinnen. Die reduzierten Wärmeverluste an die Umgebung überkompensieren bei sorgfältiger Abstimmung von Kühlmittelvolumenstrom und Heizungswärmetauscherwirkungsgrad die Einbußen an Heizungswärmetauscherwirkungsgrad bei Reduktion des Kühlmitteldurchsatzes. Für maximale Heizleistung ist es dabei insbesondere vorteilhaft, Heizungswärmetauscher in Gegenstrombauart zu verwenden, da diese bei Reduktion des Kühlmitteldurchsatzes wesentlich weniger Wirkungsgradeinbuße haben als konventionelle Kreuzstromwärmetauscher.
• Wenn in der Fahrerkabine die gewünschte Innenraumtemperatur erreicht ist, verhindert die luftseitige Regelklappe 5, dass die Innenraumtemperatur im Fahrzeug weiter ansteigt, indem ein Teil der in die Kabine geförderten Frischluft am Heizungswärmetauscher 4 vorbei geleitet wird.
• Damit steigt die Kühlmitteltemperatur am Heizungswärmetauscheraustritt und dem Öl wird weniger oder gar keine Wärme mehr entzogen. Im weiteren Verlauf der Fahrt wird i.a. die Kühlmitteltemperatur weiter steigen, speziell wenn die am Heizungswärmetauscher entnommene Wärmemenge bei warmem Innenraum zusätzlich durch ein Zurücknehmen der Gebläseleistung abnimmt. Doch auch wenn das Kühlmittel mit Temperaturen oberhalb der Thermostatöffnungstemperatur von beispielsweise 88°C aus dem Heizungswärmetauscher bzw. dem Ölkühler zum Motor zurückströmt bleibt der Thermostat 6 geschlossen, da das Kühlmittel nicht entlang des Dehnstoffelementes strömt. Damit wird sichergestellt, dass nicht unbeabsichtigt Wärme über den Kühler 8 abgegeben wird, bevor eine vollständige Erwärmung des Motors einschließlich des Kühlwassers und des Öls erfolgt ist. Optional kann die el. Pumpe 2 nach Erreichen der gewünschten Innenraumtemperatur in der Förderleistung erhöht werden, um den Wärmeeintrag ins Motoröl dadurch zu erhöhen, dass das Kühlwasser wärmer am Ölkühler ankommt. Dies ist auch deshalb vorteilhaft, weil mit Annäherung an kritische Bauteiltemperaturen bzw. an den kritischen Systemdruck eine homogenere Temperaturverteilung innerhalb des Motors anzustreben ist.
• Sobald die Motorlast bzw. die Kühlmitteltemperatur oder die Bauteiltemperatur oder der Kühlmitteldruck einen kritischen Wert überschreitet, öffnet das Zusatzventil 6bv. Damit strömt unmittelbar ein sehr hoher Kühlmittelstrom durch den Bypasszweig und durch den Motor und sorgt für einen Temperaturausgleich. Gegebenenfalls öffnet das nun von warmem Kühlmittel umströmte Dehnstoffelement des Thermostaten 6 den Kühlerkreislauf 6a und regelt auf die Thermostat-Solltemperatur von z.B. 88°C. In vielen Fällen wird es mit Blick auf einen optimalen Kraftstoffverbrauch vorteilhaft sein, das Zusatzventil 6bv nach kurzer Zeit wieder zu schließen, da die wärmeaktiven Massen im Ausgleichsbehälter und im Bypasszweig bereits reichen, um thermische Lastspitzen wegzudämpfen. Gegebenenfalls kann eine Ein/Aus-Regelung noch etwas an Kraftstoffverbrauchsvorteil nutzen, da die zeitlich mittlere Motorkühlmitteltemperatur dadurch oberhalb der Thermostatöffnungstemperatur liegt.

A flow strategy for simultaneous improvement of heating performance and fuel consumption using the cooling circuit according to FIG 6th and 5 could thus be designed particularly advantageously as follows:

• With a cold start at -10 ° C ambient temperature and 50 km / h, ie rel. low engine load, the additional valve 6bv is closed in a first step, the el.
• Auxiliary pump conveys the coolant in the in 6th direction shown. This ensures reliable defrosting of the windshields and prevents the windows from fogging up. After a minimum coolant temperature has been reached, the fan output is gradually increased so that the air mass flow into the driver's cab increases, while at the same time the air flow is no longer primarily directed through the defroster nozzles, but also in the direction of the footwell and, if necessary, in the direction of the Mannanstroemer.
• In order to maximize the cabin heating effect, it is advantageous if the coolant mass flow passes through the heating system heat exchanger 4th is set so that the coolant temperature at its outlet is noticeably below the oil temperature of the oil cooler 40 flowing engine oil. The better the degree of heat utilization of the heating system heat exchanger with relatively low coolant flows, the more heat can be obtained for heating purposes in this detour by cooling the engine oil. The reduced heat losses to the environment more than compensate for the losses in heating heat exchanger efficiency when the coolant throughput is reduced if the coolant volume flow and heating heat exchanger efficiency are carefully coordinated. For maximum heating output, it is particularly advantageous to use countercurrent heating heat exchangers, since these have significantly less loss of efficiency than conventional cross-flow heat exchangers when the coolant throughput is reduced.
• When the desired interior temperature is reached in the driver's cab, the air-side regulating flap prevents this 5 that the interior temperature in the vehicle continues to rise because some of the fresh air delivered into the cabin is at the heating system heat exchanger 4th is passed by.
• This increases the coolant temperature at the heater's heat exchanger outlet and less or no heat at all is extracted from the oil. As the journey continues, the coolant temperature will generally continue to rise, especially if the amount of heat extracted from the heating system heat exchanger also decreases when the interior is warm by reducing the fan output. But even if the coolant flows back to the engine at temperatures above the thermostat opening temperature of, for example, 88 ° C, the thermostat remains 6th closed because the coolant does not flow along the expansion element. This ensures that there is no inadvertent heat from the cooler 8th is released before the engine, including the cooling water and oil, has fully warmed up. Optionally, the el. Pump 2 after reaching the desired interior temperature, the delivery rate can be increased in order to increase the heat input into the engine oil by the fact that the cooling water arrives at the oil cooler warmer. This is also advantageous because as the critical component temperatures or the critical system pressure approach, a more homogeneous temperature distribution within the engine is desirable.
• As soon as the engine load or the coolant temperature or the component temperature or the coolant pressure exceeds a critical value, the additional valve 6bv opens. This means that a very high flow of coolant flows directly through the bypass branch and through the engine and ensures temperature equalization. If necessary, the thermostat's expansion element, around which the warm coolant flows, opens 6th the cooler circuit 6a and regulates to the set thermostat temperature of, for example, 88 ° C. In many cases, with a view to optimal fuel consumption, it will be advantageous to close the additional valve 6bv again after a short time, since the heat-active masses in the expansion tank and in the bypass branch are already sufficient to dampen thermal load peaks away. If necessary, an on / off control can still use some of the fuel consumption advantage, since the mean engine coolant temperature over time is thus above the thermostat opening temperature.

When the additional valve 6bv is open, it is in accordance with the application 6th important that the el. auxiliary pump 2 is able, even against the pressure difference, that the very high coolant throughput through the engine to the heating system heat exchanger circuit when the additional valve 6bv is open 4a imprints to promote. However, this can be achieved with relatively little effort, especially since the additional electric pump 2 only needs to convey relatively little coolant through the heater.

The previous comments on 6th focused in particular on the task of “best heating effect”. At the same time, however, the design according to 6th by simply reversing the polarity of the additional electrical pump to the circuit according to 5 can be switched and then work as a fuel-consumption-optimized system. This is always of particular interest when the requirements for cabin heating are relatively easy to meet, ie when there is little heating requirement or excess engine waste heat. Even if in such operating situations without reversing the polarity of the additional electrical pump 2 If fuel savings can be achieved, the polarity reversal leads to an additional friction loss advantage, since the cold coolant now first flows through the cylinder head and is preheated to the water jacket of the cylinder liner. Further advantages in terms of friction loss result from the extraction of cold cooling water zones in the lower area of the cylinder liner and the homogenization of the coolant and oil temperatures in the oil cooler 40 .
If there is an increased need for cooling, this application also opens accordingly 5 and 6th the additional valve 6bv and ensures safe heat dissipation via the cooler 8th . In the particularly advantageous application with an additional electric impeller pump 2 In this operating mode, the electrical drive can be dispensed with, as it runs freely at high coolant temperatures in view of the pressure gradient present and the low coolant viscosity. This protects the electrical auxiliary pump.
The arrangement according to 5 and 6th offers the very special advantage that even if the additional electronic impeller pump fails 2 The heating comfort that is common today can still be achieved by simply opening the additional valve 6bv.

Additional valves 6bv for carrying out the method according to the invention are already available on the market. Simple on / off valves with a vacuum box or with a magnet as an actuator are particularly preferred.

An additional safeguard or monitoring of the valve position is in view of the already existing monitoring of the cooling water or component temperature by means of the motor control 20th actually not necessary. This applies in particular if the valve position "Open if the actuator energy fails" is selected as the basic setting, which is possible with magnetic or vacuum actuators at no cost. Nevertheless, especially as a redundant safeguard in the first series applications, an additional valve with a safety expansion element 6bs is particularly advantageous, as in FIG 8th shown as an example. This is where the management controls 63 the Electromagnet 6bf and opens the plate 6bv against the force of the spring when electrical current is applied 62 . If the negative pressure is too great at a high engine speed, the plate 6bv is sucked up. Likewise, the plate 6bv opens when the punch 66 of the safety expansion element 6bs exceeds its limit temperature of 105 ° C., for example. These safety functions are shown here using a poppet valve as an example. In an analogous manner, however, these can also be implemented on a rotary slide valve or roller or ball valve with an external lever mechanism. If necessary, the expansion element must then protrude somewhat into the cooling water or a flow-through cooling water connection to the expansion element must be established.

The embodiment according to FIG. 1 is particularly advantageous in this context 9 , in which, instead of an expansion element, a characteristic cooling water pressure is connected to the line 69 Actuated actuator 6bx via a reciprocating piston or a membrane with a plunger 66 pressing on when a critical state is reached is self-sufficient, ie by overriding the engine control. This results in the particular advantage that the installation position of the additional valve can be selected relatively freely. The preferred position for the pressure extraction is the close range after the engine coolant pump outlet or the engine block, but also positions at the outlet from the engine head - or even at the valve inlet pipe, such as in 12th shown as an example - can be used with appropriate fine-tuning. As a special feature in this embodiment, it is not a local temperature, such as that already detected by the coolant temperature sensor, for example, that is used for redundant protection, but rather an integrating signal. As soon as vapor bubbles arise at any point in the engine when the cooling system is sufficiently filled with cooling water, the associated rise in pressure is impressed on the pressure tapping point and, if a critical value is exceeded, the additional valve 6bv opens. This dichotomy of the monitoring principles with the temperature sensor of the engine control and the self-sufficient actuator with pressurization reduces the risk of retrofitting in largely fully developed cooling circuits to a minimum. This is particularly helpful in the case of the variants with flow through the motor from the head to the block or in the case of variants with switching of the flow direction.

Especially for systems with an additional electronic pump 2 in the heating circuit, such as in 3 until 6th , indicates 10 in a further step an additional valve that no longer has the engine control 20th is controlled, but directly by a piston with a characteristic pressure 69 of the cooling water circuit is applied.

• Das autarke Zusatzventil arbeitet hier mit einem Drehschieber 106, der über den Hebel 105 und den Stößel 104 der externen Überdruckdose 100 angetrieben wird.
• Der Kühlmitteldruck gelangt über den Anschluss 103 in die Druckdose und öffnet bei Überschreiten eines Sollwerts das Ventil gegen den atmosphärischen Gegendruck zuzüglich einer Vorspannkraft. Ein erheblicher Vorteil ist hier dadurch gegeben, dass es möglich ist, den Drehschieber so zu gestalten, dass sich die Druckverluste nahezu auf die Verluste der Rohrströmung der Zu- und Ableitung 67 und 68 reduzieren. Dies macht insbesondere die nachträgliche Systemintegration des Zusatzventils 6bv sehr einfach. Noch wichtiger ist aber der Vorteil, dass sich bei diesem Aktuator bereits bewährte Fertigungseinrichtungen und Werkzeuge heutiger Serienanwendungen nutzen lassen. Die Ventilkosten werden damit extrem gering und bieten dennoch sowohl die Funktionalität des Schließens im Warmlauf als auch der gleichzeitigen Sicherheitsüberwachung gegen Überhitzen des Motors.
• Dabei kann gemäß 12 zur weiteren Systemvereinfachung in vielen Anwendungsfällen der Steuerdruck auch am Ventileintritt 67 entnommen werden, speziell wenn der Thermostat 6 und der Kühler 8 einen großen Anteil am Druckverlust im Motorkühlkreislauf aufweisen.

During the warm-up, the additional electrical pump is used here 2 It is certain that even at low engine speeds and at low system temperatures - and therefore when the additional valve 2bv is closed due to the system - heating capacity is available when required.
If a maximum permissible coolant pressure is exceeded, either because the engine speed is too high and / or because the permissible component temperature or vapor bubble density is exceeded, the flow path 67, 68 for the bypass branch is also opened here.
By doing without direct control via the engine control 20th Although part of the fuel consumption savings potential is given up, since an adjustment of the opening pressure is not possible for the entire map range of the engine, the engine cooling and the heating requirement, the advantages with regard to the heating are largely retained.
By eliminating the solenoid valve in the vacuum actuator and the elimination of the lifting magnet in the directly controlled cooling water solenoid valve, the valve costs are almost halved. This is particularly true of the valve configuration according to a variant of the invention 11 clear:

• The self-sufficient additional valve works here with a rotary slide valve 106 that is about the lever 105 and the plunger 104 the external overpressure unit 100 is driven.
• The coolant pressure comes through the connection 103 into the pressure cell and opens the valve against the atmospheric counterpressure plus a pre-tensioning force when a setpoint is exceeded. A considerable advantage is given here by the fact that it is possible to design the rotary slide valve in such a way that the pressure losses are almost the same as the losses in the pipe flow of the inlet and outlet 67 and 68 to reduce. In particular, this makes the subsequent system integration of the additional valve 6bv very easy. Even more important, however, is the advantage that proven production facilities and tools for today's series applications can be used with this actuator. The valve costs are extremely low and still offer both the functionality of closing during warm-up and simultaneous safety monitoring against overheating of the motor.
• In doing so, according to 12th To further simplify the system, in many applications the control pressure also at the valve inlet 67 can be removed, especially if the thermostat 6th and the cooler 8th have a large share in the pressure loss in the engine cooling circuit.

Control via a characteristic coolant pressure is particularly favored by the fact that the return flow from the expansion tank is integrated 9 to the thermostat 6th or to the engine cooling water pump 7th is always open, like in 1-6 shown. A connection of the return on the cold cooler side would be more problematic here, since the system pressures then shift more strongly when the thermostat is open and closed. The integration of the ventilation line 9a behind the additional valve 6bv and the return from the expansion tank 9 In this variant according to the invention, it is not only an increased risk of cavitation in the engine coolant pump that helps 7th and to avoid the heat losses of the ventilation circuit in the warm-up phase, but it is also helpful on the way to an extremely cost-effective improvement in fuel consumption and, if necessary, the heating output, especially if, for example, an electric auxiliary pump is used anyway to maintain the cabin heating when the engine is not running 2 should be provided in the heating circuit.

Claims (44)

Method for operating a cooling and heating circuit for motor vehicles with an internal combustion engine (1), which is cooled by means of a coolant circulated by an engine coolant pump (7), with a self-sufficient thermostatic valve (6) which controls a coolant temperature and a coolant throughput through the internal combustion engine (1) and regulates a vehicle radiator (8) and a bypass branch (6b) with an additional valve (6bv) which can be influenced by an electronic engine control (20) and which additionally varies the coolant throughput through the internal combustion engine (1) as a function of its cooling requirement, characterized in that a heating heat exchanger circuit and other coolant branches through which flow can flow when the autarkic thermostat valve (6) is closed are arranged parallel to one or more pressure sinks in a flow branch that can be influenced by the additional valve (6bv) and that the heating heat exchanger circuit and this other when the autarkic thermostat is closed Valve (6) through which coolant branches can flow with reduced cooling or heating requirements, despite the rotating engine coolant pump (7), a reduced pressure difference up to zero pressure difference is imposed, so that the additional valve (6bv) partially or completely closes. Method for operating a cooling and heating circuit for motor vehicles with an internal combustion engine (1), which is cooled by means of a coolant circulated by an engine coolant pump (7), with a self-sufficient thermostatic valve (6) which controls a coolant temperature and a coolant throughput through the internal combustion engine (1) and regulates a vehicle radiator (8) and a bypass branch (6b) with an additional valve (6bv) which can be influenced by an electronic engine control (20) and which additionally varies the coolant throughput through the internal combustion engine (1) as a function of its cooling requirement, characterized in that a ventilation circuit as well as when the self-sufficient thermostat valve (6) is closed, the coolant branch through which the flow can flow is arranged parallel to one or more pressure sinks in a flow branch that can be influenced by the additional valve (6bv) and that the ventilation circuit with reduced cooling or heating requirements is thereby despite the rotating engine coolant pump (7) a reduced pressure difference up to zero pressure difference is imposed, that the additional valve (6bv) closes partially or completely, and that the closing of the additional valve (6bv) sets an operating mode without any engine flow with coolant. Method for operating a cooling and heating circuit for motor vehicles with an internal combustion engine (1), which is cooled by means of a coolant circulated by an engine coolant pump (7), with a self-sufficient thermostatic valve (6) which controls a coolant temperature and a coolant throughput through the internal combustion engine (1) and regulates a vehicle cooler (8) and a bypass branch (6b) with an additional valve (6bv) which can be influenced by an electronic engine control (20) and which additionally varies the coolant throughput through the internal combustion engine (1) as a function of its cooling requirement, characterized in that a circuit for the flow through an oil cooler (40) as well as when the self-sufficient thermostat valve (6) is closed, the coolant branch through which the flow can flow is arranged parallel to one or more pressure sinks in a flow branch that can be influenced by the additional valve (6bv) and that this circuit with the oil cooler (40) with reduced cooling or heating requirement dad A reduced pressure difference down to zero pressure difference is imposed despite the engine coolant pump (7) rotating, so that the additional valve (6bv) closes partially or completely, and that the closing of the additional valve (6bv) sets an operating mode without any engine flow with coolant. Method for operating a cooling and heating circuit for motor vehicles with an internal combustion engine (1), which is cooled by means of a coolant circulated by an engine coolant pump (7), with a self-sufficient thermostatic valve (6), which controls the coolant temperature and a coolant flow rate through an internal combustion engine (1) and regulates a vehicle cooler (8) and a bypass branch (6b) with an additional valve (6bv) which can be influenced by an electronic engine control (20) and which additionally varies the coolant throughput through the internal combustion engine (1) as a function of its cooling requirement, characterized in that at least two Can also be flown through when the self-sufficient thermostatic valve (6) is closed Coolant branches are arranged parallel to one or more pressure sinks in a flow branch that can be influenced by the additional valve (6bv) and that even when the autarkic thermostat valve (6) is closed, there is a reduced pressure difference in these branches, with a reduced cooling or heating requirement despite the engine coolant pump (7) rotating up to the pressure difference zero is impressed that the additional valve (6bv) closes partially or completely. Method according to one of the Claims 1 - 4th , characterized in that a flow-determining pressure difference in a / in the heating heat exchanger circuit and other coolant branches that can flow even when the self-sufficient thermostatic valve (6) is closed is generated or increased when there is a need for cooling or heating, in that the additional valve (6bv) opens partially or completely. Method according to one of the Claims 1 or 4th , characterized in that the closing of the additional valve (6bv) sets an operating mode without any engine flow with coolant. Method according to one of the Claims 1 - 6th , characterized in that the coolant for a / the heating heat exchanger circuit is withdrawn downstream of the additional valve (6bv) and fed back in upstream of the engine coolant pump (7). Method according to one of the Claims 1 - 7th , characterized in that the coolant for a / the heating heat exchanger circuit is taken downstream of the engine coolant pump (7) and fed back in upstream of the additional valve (6bv). Procedure according to Claim 4 , characterized in that an additional electrical pump (2) ensures a defined flow rate in a heating heat exchanger circuit. Procedure according to Claim 4 or 9 , characterized in that an / the electrical auxiliary pump (2) ensures temperature compensation within the internal combustion engine (1) when the bypass branch (6b) is closed with the auxiliary valve (6bv). Procedure according to Claim 4 , 9 or 10 , characterized in that one / the el. auxiliary pump (2) with the bypass branch (6b) closed with the auxiliary valve (6bv) within the internal combustion engine (1) brings about a coolant flow direction that is reversed compared to the full-load conveying direction of the engine coolant pump (7). Procedure according to Claim 10 or 11 , characterized in that the self-sufficient thermostatic valve (6) remains cooler than the cooling water on a cylinder liner. Method according to one of the Claims 4 or 9 - 12th , characterized in that the return of the coolant in the heating heat exchanger circuit is arranged downstream of a temperature-regulating actuator in the self-sufficient thermostatic valve (6). Method according to one of the Claims 1 - 13th , characterized in that an expansion tank (9) is returned on the engine side upstream of the engine coolant pump (7) and that an inlet to the expansion tank (9) is connected downstream of the additional valve (6bv). Method according to one of the Claims 1 - 14th , characterized in that by keeping the additional valve (6bv) closed, the self-sufficient thermostatic valve (6) is at least temporarily prevented from opening completely or partially due to the lack of flow to an actuator and thus the engine coolant temperature can be freely adjusted by the engine control (20). Method according to one of the Claims 1 - 15th , characterized in that an / the oil cooler (40) is arranged downstream of the additional valve (6bv) parallel to the pressure sinks. Method according to one of the Claims 4 or 9 - 13th , characterized in that an / the electrical auxiliary pump (2) at least temporarily reverses the direction of flow within the internal combustion engine (1). Procedure according to Claim 17 , characterized in that the direction of flow is reversed by reversing the polarity of the additional electrical pump (2). Procedure according to Claim 18 , characterized in that the direction of flow is reversed by closing the additional valve (6bv) and simultaneously operating the electrical additional pump (2). Method according to one of the Claims 9 - 13th or 17th - 19th , characterized in that by reversing the delivery direction of the electronic auxiliary pump (2), a switch is made between a fuel consumption-oriented and a heating-output-oriented operating mode. Method according to one of the Claims 4 , 9 - 13th or 17th - 20th , characterized in that a heating flow is ensured at least temporarily by one / the additional electric pump (2), and that instead of controlling the additional valve (6bv) by means of the motor controller (20), the auxiliary valve (6bv) is controlled independently. Procedure according to Claim 21 , characterized in that a coolant pressure acts directly on an actuator of the additional valve (6bv). Procedure according to Claim 22 , characterized in that the coolant pressure is taken in an area with high static pressure. Method according to one of the Claims 1 - 5 , characterized in that by closing the additional valve (6bv) in a statutory exhaust gas test in the first ECE cycles, an operating mode without any engine flow with coolant can be set, and that the additional valve (6bv) in phases with increased cooling requirements from the engine control ( 20) can be opened. Method according to one of the Claims 1 - 24 , characterized in that an air-side regulating flap (5) can prevent the interior temperature in the vehicle from rising further by directing part of the fresh air conveyed into the cabin past the heating system heat exchanger (4). Method according to one of the Claims 1 - 20th or 24 , characterized in that the additional valve (6bv) controllable by the engine controller (20) is the only valve with which the engine controller (20) can intervene in a coolant circuit through which the self-sufficient thermostatic valve (6) can flow. Method according to one of the Claims 1 - 20th , 24 or 26th , characterized in that the additional valve (6bv) is controlled electrically and an expansion element (6bs) when a maximum permitted coolant temperature increase above the nominal temperature of the self-sufficient thermostatic valve (6) is exceeded, the electrical control self-sufficient override and a flow path (67, 68) for the bypass branch opens. Method according to one of the Claims 1 - 20th , 24 or 26th , characterized in that the additional valve (6bv) is controlled electrically and an actuator (6bx) charged with the coolant pressure (69) overrides the electrical control independently when a maximum permissible coolant pressure is exceeded and a flow path (67, 68) for the bypass branch (6b ) opens. Method according to one of the Claims 1 - 20th , 24 or 26th , characterized in that the additional valve (6bv) is controlled electrically and an actuator to which the coolant pressure (69) is applied opens a flow path (67, 68) for the bypass branch (6b) when a maximum permissible coolant pressure is exceeded. Procedure according to Claim 29 , characterized in that a rotary slide valve is used as an additional valve (6bv), which is driven by an overpressure cell. Procedure according to Claim 29 , characterized in that a rotary slide valve is used as an additional valve (6bv), which is driven by an overpressure cell and that the coolant pressure opens the valve against a pressure chamber defined internal pressure plus a biasing force when a target value is exceeded. Procedure according to Claim 30 or 31 , characterized in that a coolant control pressure for the pressure cell is taken from the coolant at a valve inlet. Device for cooling and heating motor vehicles with an internal combustion engine (1), which is cooled by means of a coolant circulated by an engine coolant pump (7), with a self-sufficient thermostatic valve (6), which controls a coolant temperature, a coolant throughput through the internal combustion engine and a vehicle radiator (8) regulates and a bypass branch (6b) with an additional valve (6bv), which additionally varies the coolant throughput through the internal combustion engine (1) depending on its cooling requirement, characterized in that a heating heat exchanger circuit and other coolant branches through which the self-sufficient thermostat valve (6) can flow parallel to a or several pressure sinks are arranged in a flow branch that can be influenced by the additional valve (6bv) and that the heating heat exchanger circuit and these other coolant branches through which the autarkic thermostat valve (6) can flow when the cooling or heating requirement is reduced as a result, in spite of the rotating engine coolant pump (7), a reduced pressure difference up to zero pressure difference can be impressed that the additional valve (6bv) partially or completely closes. Device for cooling and heating motor vehicles with an internal combustion engine (1), which is cooled by means of a coolant circulated by an engine coolant pump (7), with a self-sufficient thermostatic valve (6), which controls a coolant temperature, a coolant throughput through the internal combustion engine and a vehicle radiator (8) regulates and a bypass branch (6b) with an additional valve (6bv), which additionally varies the coolant throughput through the internal combustion engine (1) depending on its cooling requirements, characterized in that a ventilation circuit (9a) as well as a coolant branch through which the self-sufficient thermostat valve (6) can flow parallel to one or more pressure sinks in one that can be influenced by the additional valve (6bv) Flow branch is arranged and that the ventilation circuit can be impressed with a reduced pressure difference up to zero pressure difference in spite of the rotating engine coolant pump (7) with a reduced cooling or heating requirement, that the additional valve (6bv) partially or completely closes, and that the closing of the additional valve (6bv) can set an operating mode without any engine flow with coolant. Device for cooling and heating motor vehicles with an internal combustion engine (1), which is cooled by means of a coolant circulated by an engine coolant pump (7), with a self-sufficient thermostatic valve (6), which controls a coolant temperature, a coolant throughput through the internal combustion engine and a vehicle radiator (8) regulates and a bypass branch (6b) with an additional valve (6bv), which additionally varies the coolant throughput through the internal combustion engine (1) depending on its cooling requirement, characterized in that a circuit for flowing through an oil cooler (40) as another even when the self-sufficient thermostatic valve is closed (6) through which the coolant branch can flow is arranged parallel to one or more pressure sinks in a flow branch that can be influenced by the additional valve (6bv) and that this circuit with the oil cooler (40) has a reduced pressure differential with a reduced cooling or heating requirement despite the engine coolant pump (7) rotating Enz up to the pressure difference zero can be impressed that the additional valve (6bv) closes partially or completely and that the closing of the additional valve (6bv) can set an operating mode without any engine flow with coolant. Device for cooling and heating motor vehicles with an internal combustion engine (1), which is cooled by means of a coolant circulated by an engine coolant pump (7), with a self-sufficient thermostatic valve (6), which controls a coolant temperature, a coolant throughput through the internal combustion engine and a vehicle radiator (8) regulates and a bypass branch (6b) with an additional valve (6bv), which additionally varies the coolant throughput through the internal combustion engine (1) depending on its cooling requirement, characterized in that at least two coolant branches through which the self-sufficient thermostat valve (6) can flow parallel to one or a plurality of pressure sinks are arranged in a flow branch that can be influenced by the additional valve 6bv and that even when the autarkic thermostat valve (6) is closed, the coolant branches through which there is a reduced cooling or heating requirement despite the engine coolant pump (7) rotating fference up to the pressure difference zero can be impressed that the additional valve (6bv) closes partially or completely. Device according to one of the Claims 33 - 36 , characterized in that a flow-determining pressure difference in the heating heat exchanger circuit and other coolant branches that can flow through even when the autarkic thermostat valve (6) is closed can be generated or increased when there is a need for cooling or heating by opening the additional valve (6bv) partially or completely. Device according to Claim 33 or 36 , characterized in that the closing of the additional valve (6bv) can set an operating mode without any engine flow with coolant. Device according to one of the Claims 33 - 38 , characterized in that an air-side regulating flap (5) can prevent the interior temperature in the vehicle from rising further by leading part of the fresh air conveyed into the cabin past the heating system heat exchanger (4). Device according to one of the Claims 33 - 39 , characterized in that the additional valve (6bv) can be controlled by an engine control (20) and that the additional valve (6bv) is the only valve with which the engine control (20) can intervene in a coolant circuit through which the autarkic thermostatic valve (6) is closed . Device for performing the method according to Claim 1 and for cooling and heating motor vehicles with an internal combustion engine (1), which is cooled by means of a coolant circulated by an engine coolant pump (7), with: ), • a bypass circuit leading through the internal combustion engine (1) and a bypass branch (6b), • a ventilation circuit leading through the internal combustion engine (1) with an expansion tank (9), • a heating heat exchanger circuit leading through the internal combustion engine (1) with a heating heat exchanger ( 4), characterized in that • the ventilation circuit and the heating heat exchanger circuit lead through a coolant line section through which at least these two circuits can flow and which has a 2-way additional valve (6bv), and • that an air-side control flap (5) is available to prevent that can further an interior temperature in the vehicle increases when a desired interior temperature is reached in the driver's cab, in that part of the fresh air conveyed into the cab is directed past the heating system heat exchanger (4). Device according to Claim 41 , characterized in that the opening of the additional valve (6bv) is provided in driving situations in which the air-side temperature control flap (5) prevents the interior temperature in the vehicle from rising further when the desired interior temperature is reached in the driver's cab. Device according to Claim 41 or 42 , characterized in that the additional valve (6bv) controllable by the engine control (20) is the only valve which can intervene in the heating heat exchanger circuit when the autarkic thermostat valve (6) is closed. Device according to one of the Claims 33 - 43 , characterized in that the / a heating heat exchanger (4) is designed in a countercurrent design.

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